1. Field of Invention
This invention relates to a display module. This invention further relates to a portable electronic device, for example a mobile phone, a PDA etc., comprising such a display module.
2. Related Art
Typically, display modules comprise a liquid crystal display (LCD), which further comprises two substrates with respective sheets of polarizing films on each of the substrates and a liquid crystal material between the two substrates. On one of the substrates, the LCD further comprises a common electrode plane of indium-tin oxide covering the entire area of the LCD. The other substrate is provided with individual electrodes for each pixel of the display. The display module further comprises light enhancement sheets and diffuser sheets, a lightguide, a reflector sheet, which are housed together with the LCD into a housing unit. Generally, a separate black sticker is placed below a driver IC, which is placed on the lower substrates, to block light coming from the backlight. These types of displays are well known in the art and have been improved over time.
An embodiment of an LCD supporting structure is disclosed in U.S. Pat. No. -20030071941-A1. The LCD comprises a front substrate and a rear substrate, the rear substrate having an edge extending beyond the front substrate, this extended part of the rear substrate forming a non-overlapping region between the front substrate and the rear substrate. A liquid crystal material is present between the overlapping region of the front substrate and the rear substrate. The rear polarizer of the LCD module is fixed to a lightguide plate of a back lighting module using a double-sided adhesive tape (DSA). The DSA is made of black polyethylene terephtalate (PET) or the likes having light blocking properties. Adhesive layers formed on both surfaces of the black PET. A driver IC is positioned on the extended part of the rear substrate. A connecting foil is electrically connected to the IC driver which drivers the driver IC.
A disadvantage with the LCD module described above is that the LCD module is vulnerable to mechanical stress, for example during a fall or the stress created due to the back bending of the foil connected to the driver IC. This mechanical stress leads to cracking or breaking of the rear substrate thereby making the liquid crystal material flow out which is poisonous and harmful to the user. Additionally, the connecting foil, which is bent backwards, generates an uplifting force potentially separating the components of the LCD module, for example peeling off the rear polarizer from the rear substrate. This latter problem may be overcome by providing the LCD module with an upper bezel, however this has the disadvantage of increasing the thickness of the display module.